Hydraulic pump-unloader.



L. A. VIGNERI.

HYDRAULIC PUMP UNLOADER. MPLICATIDN FILED APR. 11. 1911.

Patented May 28,1918.

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L. A. VIGNERI.

HYDRAULIC PUMP UNLOADER.

wwucmmu FILED APR. 11, 1911.

1,267,720. Patented May 28,1918.

2 SHEETS-SHEET 2.

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LEONARD A. VIGNEBI, 0F PITTSBURGH, PENNSYLVANIA.

HYDRAULIC PUMP-UNLOADER.

' Specification of Letters Patent.

Patented May 28, 1918.

Application filed April 11, 1917. Serial No. 161,182.

To all whom it may concern:

Be it known that I, LEONARD A. Vioxnni, a citizen of the United States. and a resident of the city of Pittsburgh. in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Hydraulic Pump-Unloaders, of which the following is a specification.

My invention relates to a hydraulic unloading device adapted for use in connection with a fluid pressure pumpdischarging into an accumulator wherein it is desired that the discharge of fluid from the pump to the accumulator shall be controlled either manually or automatically without affecting the operation of the pump. More specifically, it relates to an unloading device wherein the unloading action is produced by effecting a communication or by-passing through the unloading device between the discharge and suction manifolds of the pump. In use in connection with accumulators in hydraulic work, such as those for operating hydraulic presses, riveting machines, hammers, etc., my unloading device offers a means for automatically regulating the stroke thereof, the unloading device causing the pump to run light or Without discharging into the accumulator when the latter has reached the predetermined limit of its stroke, and maintaining the pump in this condition until the return of the accumulator to a predetermined point.

The objects of my invention are to provide an unloading device for pumps discharging into an accumulator which may be readily interposed in the pump circuit by connection of the intake and discharge manifolds of the pump which will effect the unloading of the pump positively and freely at the predetermined moment, and which will eliminate shocks on the valves of the pump on resumption of load by the latter. Further objects of my invention will hereinafter appear.

In accordance w th my invention I provide in an unloading device means for cutting ofl the supply of water or fluid to the pump simultaneously with the by-passing of the water or fluid from the discharge to the suction manifold of the pump, thereby equalizing the pressure on the valves of the pump and eliminating shocks thereupon when the pump is again loaded.

' An embodiment of my invention is illustrated in the accompanying drawings, wherein Figure l is a somewhat diagrammatic rep resentation in elevation of the unloading device and its connections with a pump and an accumulator, shown in this instance as a hydraulic press. i

Fig. 2 is a longitudinal section through the unloading device, and

Fig. 3 is a transverse section iherethrough at right angles to Fig. 2. i

The unloading device, 5 is connected upon one hand, to the suction and discharge manifolds 6 and 7, respectively, of the pump 8. and on the other hand to the water supply pipe 9, and to pipe 10 discharging to the accumulator 57.

The intake 11 0f the unloading device itself divides into two portions 12 and 13 in order to pass around the operating cylinder 14 for the by-pass valve operating mechanism, these passages joining each other to form the passage 15 which opens into the suction passage 16, to Wlll('ll the suction manifold 6 of the pipe connects. A check valve 17 is provided at the point at which the passage 15 opens into the suction passage 16, this valve, in the embodiment shown comprising a facing of alloy. habbitt or the like 18, a stem 19, and a spring cap 20, and being retained against the seat 21, which is formed as a spider with a central guide for the valve stem 19, by spring 22 surrounding the stem 19 and retained within the cap 20. The suction passage 16 is provided with a removable plate or the like 23,

whereby access to the check valve may be had.

The suction passage 16 also connects with the discharge passage 24 through opening 25, this opening being closed when the pump is running under load by means of by-pass valves. These by-pass valves are. in the c ne, bodiment shown, two in number and COIlSlSlL.

of a main by-pass valve 26 seated upon the opening 25 and provided withsuitable Babbitt or alloy. facings, if desired. and with openings or holes 28 passing entirely therethrough, and an auxiliary or pilot by-pass valve 29 which rests upon the main by-pass valve 26 and closes the holes 28 therein on normal operation of the pump under load. Both by-pass valves are mounted upon a valve stem 30, the auxiliary or pilot by-pass valve retained between a shoulder 31 and a lock nut 32, the latter also being utilized as a means for regulating the lift of the valve. The main by-pass valve is mounted upon the valve stem 30 below the shoulder 31, a second shoulder 33 being provided at a distance below the shoulder supporting the auxiliary by-pass valve 29 somewhat greater than the thickness of the main b ass valve 26 so as to permit of a slight movement of the valve stem 30 in the upward direction before lifting the valve 26.

The valve stem 30 passes upward through the top of the passage 24, and through a suitable stufing box 34, and terminates in a spring cap 35. This cap is surrounded by a yoke 36 provided with a regulating screw 37 to which isattached a second spring cap 38 opposite the spring cap 35. A spring 39 is placed between the two spring caps 35 and 38 and tends constantly to torce the valve stem 30 downwardly and to maintain the by-pass valves 26 and 29 seated. The force with which the spring 39 acts may be regulated by means of the screw 3?, locked by a lock nut 40.

Below the by-pass valves 26 the valve stem 30 passes downwardly through the suction passage 16 and the stufling box 41 into the operating cylinder 14, in which it terminates in piston 42, which is normally positioned near the bottom of the operating chamber 14 when the by-pass valves are closed. In the specific embodiment shown this piston comprises a body 43, a cup leather 44, a follower 45 and a spring 46, the whole being united by lock nut 47.

The bottom of the operating cylinder 14 is closed by a head 48 provided with a channel 49 communicating with the interior of the cylinder and with an intersecting channel 50. A three-way valve 51 is also pro- 'vided which in one extreme position cuts oil the passage 49 and makes connection between the passage 50 and the upper portion of the passage 49 and which in the other extreme position closes the channel 50 and opens the channel 49. The channel 50 is connected to a water inlet pipe 52 and the end of the channel 49 is connected to the water outlet Or discharge pi e 53. The three-way valve 51 is operated y means of lever 54. The movement of this valve may be efiected in any suitable manner. As illustrated in Fig. 1, movement in one direction, namely that opening the outlet 53 to the passage 49,

may be efiected by a weight 55, and in the other direction by means controlled by the accumulator 57, illustrated as a cable 56 provided with suitable pulley arrangements and connected to the lever 54 in such manner that on the plunger rising to a predetermined point, stop 58 on the cable operates the lever 54 and the valve 51 to sheet unloading and the operating cylinder was on dropping to another predetermined point the lever and valve are operated in the opposite dlrectionby stop 59. l The manner in wh1ch my unloading device is connected in the system with the water supply, the pump and the discharge from the pump to the accumulator-has already been described. In operation, when the pump 18 discharging through the discharge passage 24 of the unloading device to the accumulator, the by-pass valves 26 and 29 are ma ntained in the closed position by the spring 39, the piston 42 being approximately at the bottom of the cylinder 14, and water enters freely through the passages 11, 12, 13, 1-5 and 16, check valve 17 permitting free passage thereof. A normal intake and dis charge by the pump is thus permitted. This discharge, passing to the accumulator, finally brings the latter to the predetermined final posltion at which operation of the lever 54 and the three-way valve 51 is elfected. Valve 51 is then partially rotated to permit commun cation of passage 50 with the upper portion of passage 49 and to out ofi discharge into discharge pipe 53. Water then enters from the inlet pipe 52, passing into 14 below the piston 42, tending to force the latter upwardly aga nst the action of the spring 39. lhe auxiliary by pass valve 29, being rigidly attached to the valve stem 30, moves upwardly with the latter under the action of the water under piston 42, while the main by-pass valve 46 is held in osition by the water pressure 111 passage 24, sing allowed a limited amount of free movement before being engaged by the shoulder 33 on the valve stem 30. The upward movement of auxiliary by-pass valve 29 relative to the main by-pass valve 26 opens the ports or holes 28 in the latter and thereby permits equalization of the water pressure on both sides of the by-pass valveand facilitatesits movement by the continued upward movement of the valve stem 30, efiected by the continued influx of water in the bottom of the cylinder 14.

As a result of the opening of the by-pass valves 26 and 29., communication is effected through the opening 25 between the discharge passage 24 and the suction passage 16. The higher pressure of the fluid in pas-- sage 24 causes its flow into the passage 16, forces the check valve 17 to close, thereby cutting off intake of water from the passages 11, 12, 13 and 15, and effecting a closed path of circulation between the discharge and suct on manifolds of the pump. The latter con tinues to operate, the water, however. flowing in a closed path through the passages 24,]

25 and 16 in the unloading device and through the pump itself, thus equalizing the pressure on both the suction and discharge valves in the pump and preventing shocks on resumption of its load. In reverse operation, when the accumulator, press plunger or the like has reached its other extreme position and it is desired that the pump resume its load, valve 51 is rotated to open the passage 49 and to cut oil? passage 50, thereby paired. In the embodiment illustrated, it

is formed of a plurality of relatively simple castings, securely held together by suitable studs or bolts and of such design as to be readily removable and reparable. It is obvious that the precise form and design of the construction is not of the essence of my in vention, but that these may be varied within such limits as will be readily apparent to any person skilled in the art.

I claim:

1. In an unloading device for fluid pumps, means for shutting oil supply of fluid to the intake of the pump and means for diverting the discharge from the pump to its intake.

2. In an unloading device for fluid pumps, asupply passage for supplying fluid to the intake of the )ump, means for diverting the discharge rom the pump to its intake and for thereby effecting closure of the supply passage.

3. In an unloading device for fluid pumps, a supply passage for supplying fluid to the intake of the ump, means for divertmg the discharge rom the pump to its intake, and a check valve adapted to close said supply passage when said diversion takes place.

4. In an unloading devicefor fluid pumps, a suction passage intended to communicate with the intake of the pump, a discharge passage intended to commuicate with the discharge of the pump, a supply passage communicating with the suction passage, means for effecting communication between the discharge and supply passages and check valve adapted to close said suppl passage When such communication is efl fected.

In an unloading device for fluid pumps, a suction passage intended to communicate with the intake of the pump, a discharge passage intended to communicate with the discharge of the pump and with an accumulator, the suction passage opening into the, discharge passage, a by-pass valve mechanism normally closing off the suction passage from the discharge mechanism, a supply passage communicating with the suction passage and a check valve adapted to close off said supply passage when the bypass valve is opened.

6. In an unloading device for fluid pumps, a suction passage intended to communicate with the intake of the pump, a discharge passage intended to communicate with the discharge ofthe pump and with an accumulator, the suction passage opening into the discharge passage, by-pass valve mechanism for closing off the suction passage from the discharge mechanism, means for normally retaining said by-pass valve mechanism in the closed state, means for opening said by-pass .valve mechanism, a supply passage communicating with the suction passage and a check valve adapted to close ofl said supply passage when the bypass valve is opened.

7. In an unloading device for fluid pumps, a suction passage intended to communicate with the intake of the pump, a discharge passage intended to communicate with the discharge of the pump and with an accumulator, the suction passage opening into the discharge passa e, by-pass valve mechanism for closing 0 the suction passage from the discharge mechanism, said bypass valve mechanism comprising a main by-pass valve provided with by-pass ports and an auxiliary by-pass valve operatively connected thereto and closing said by-pass ports, means fol-normally maintaining said by-pass valve mechanism closed, means for opening the auxiliary by-pass valve and subsequently opening the main by-pass valve, a supply passage communicating with the suction passage and a check valve adapted to close off, said supply passage When the by-pass valve mechanism is open.

8. In an unloading device for fluid pumps, a suction passage intended to communi cate with the intake of the pumps, a discharge passage intended to be interposed between the discharge of the pump, and an accumulator, the suction passage opening into the discharge passage, by-pass valve mechanism for closing off the suction passage from the discharge mechanism, a spring normally closing the by-pass valve mechanism, a hydraulic plunger for opening said by-pass valve mechanism, means for operating the hydraulic plunger controlled by the accumulator, a supply passage communicating with the suction passage and a the by-pass valve is open LEONARD A. VIGNERI.

passage when 

